xfs: fix kernel memory exposure problems

commit bf9216f922612d2db7666aae01e65064da2ffb3a upstream.

Fix a memory exposure problems in inumbers where we allocate an array of
structures with holes, fail to zero the holes, then blindly copy the
kernel memory contents (junk and all) into userspace.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index 66e881790c17109496e21bd5e2d7d21f5ecc7fe5..d8a77dbf4e3a570ac70861fb0d0f4a08d374a2ec 100644 (file)
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -585,7 +585,7 @@ xfs_inumbers(
                return error;
 
        bcount = MIN(left, (int)(PAGE_SIZE / sizeof(*buffer)));
-       buffer = kmem_alloc(bcount * sizeof(*buffer), KM_SLEEP);
+       buffer = kmem_zalloc(bcount * sizeof(*buffer), KM_SLEEP);
        do {
                struct xfs_inobt_rec_incore     r;
                int                             stat;